hwrng: stm32 - don't read if data is not available

spasdeloup · ashishverma2691 · commit 94c9fea3a7f7 · 2023-09-13T14:02:17.000+02:00
If buffer is being filled up, stop reading instead of reading 0. Change-Id: Idbb44823dbf701793f5af88ca7c2b4fa2a050230 Signed-off-by: Sebastien PASDELOUP <sebastien.pasdeloup-ext@st.com> Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/326899 ACI: CITOOLS <MDG-smet-aci-reviews@list.st.com> Reviewed-by: Gatien CHEVALLIER <gatien.chevallier@st.com> Domain-Review: Gatien CHEVALLIER <gatien.chevallier@st.com>
diff --git a/drivers/char/hw_random/stm32-rng.c b/drivers/char/hw_random/stm32-rng.c
@@ -64,6 +64,9 @@ static int stm32_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 					"bad RNG status - %x\n", sr))
 				writel_relaxed(0, priv->base + RNG_SR);
 			break;
+		} else if (!sr) {
+			/* The FIFO is being filled up */
+			break;
 		}
 
 		*(u32 *)data = readl_relaxed(priv->base + RNG_DR);

Original file line number	Diff line number	Diff line change
`@@ -64,6 +64,9 @@ static int stm32_rng_read(struct hwrng rng, void data, size_t max, bool wait)`
`64`	`64`	`"bad RNG status - %x\n", sr))`
`65`	`65`	`writel_relaxed(0, priv->base + RNG_SR);`
`66`	`66`	`break;`
	`67`	`+ } else if (!sr) {`
	`68`	`+ /* The FIFO is being filled up */`
	`69`	`+ break;`
`67`	`70`	`}`
`68`	`71`
`69`	`72`	`(u32 )data = readl_relaxed(priv->base + RNG_DR);`